Adjustable bore gauge



Patented Mar. 25, 1952 '1...-- .;..UNITED STATES PATENT OFFICE.

ADJUSTABLE BORE GAUGE GeorgeD. Hayden, Newport,-Mi'ch-.Application-April 29, 194%,.Serial -No. 744,587

ZICl'aims. (CE SL162? The present invention relates to instruments forinternal measurements or distances between twopoints or walls in manyplaces where exact measurements are inconvenient, such as. machine workof many kinds or bored or' drilled holes- In the determination of sizesand of irregularities, such as taper, out-of-round, etc. of bored ordrilled holes, the usual shop'practice involves the use of calipers,plug gauges and the like.

With plug gauges it is obviously difilcult if not entirely impossible todetermine anything about the holes other than whether the plug willenter or not. With calipers, an experienced operator can determineapproximately the size and shape, but not with suflicient accuracy forpurposes.

The present invention has among its objects the provision of a device,the use of which enables an operator to determine with great accuracythe hole size and its condition, i. e. Whether it is truly cylindrical.

Another object is to provide an instrument which has a wide range inhole sizes.

Still other objects and advantages will be apparent to those skilled inthe art upon reference to the following description and the accompanyingdrawings in which Fig. 1 is a side elevation of the device with partsbroken away.

Fig. 2 is a section on line 22 of Fig. 1.

Fig. 3 is a section on line 3--3 of Fig. 1.

Fig. 4 is a side elevation on an expander.

Fig. 5 is an end elevation of the same.

Fig. 6 is a more or less diagrammatic view showing the device withexpansion means in use.

As shown in the drawings, the device comprises a pair of bars and IIprovided with straight outer edges and having their inner edges inclinedtoward the center from both ends. These inner edges IDA and HA will beprovided with dovetails, as shown at l2 in Figs. 2 and 3, and at theapex of the angles produced by the meeting of the inclined portions,will be drilled suitable holes for the reception of pins I3.

The pins l3 are fixed in or integral with a small rectangular bearingblock l4 serving as a bearing for the reduced portion IA of the shaftl5. The shaft IS on one side of block I4 is threaded as far as the endsof bars 10 and II and is extended beyond and knurled as at I5B toprovide a suitable handle or means to rotate the shaft. I

At the other side of block I4 is an externall threaded sleeve IS, thediameter and threads 2 exactly" matching those on the handle end, butbeing, of opposite pitch. This sleeve extends beyond the ends of bars 10and H and upon the extendedend'softhe sleeve l6 and reduced shaftportion. 15A is mounted a collar H, a pin 18 passing. through theseparts to fix them against relative rotation and' against relativeendwise movement.

Mounted upon the threaded shaft and sleeve is a pair of traveling nuts20, which are preferably of the same thickness as bars II] and II, andwhich are dovetailed to fit the mating dovetails l2 on the bars.Rotation of shaft [5 will therefore cause the nuts 20 to move toward orfrom the block I4 and thereby move the bars l0 and II from or towardeach other with parallel movement.

The outer edge or face of bar ID will be rounded on a radius equal to orless than half the total width of the device and will be hardened andground. The outer edge or face of bar II will be provided with alongitudinal dovetail 25 rounded on its outer face with its radius thesame as that of the face of bar It).

It is, of course, obvious that the outer edge faces of bars l0 and Hmust be parallel and that the edge face of bar [0 be parallel with theedge faces of the later described expander bars.

In using the device, it may be placed in the hole or between the pointsto be examined, and will be expanded by rotating handle 15B to fit thehole. It may then be withdrawn and measured with a suitable micrometer.

In order to provide for a greater range of hole sizes, a series ofexpanders such as the one shown at 26 or such as is shown in Figs. 4 and5 will be used. The expander 26 will be used for a small increment whilea series of bars of different widths such as that shown in Figs. 4 and 5will be used singly or in combinations for other and greater increments.The wider expanders will consist of a bar, such as shown at 30, havingdovetails 30A and 303 along two opposite edges of which the dovetails30A is arranged to coact with the dovetails 25 on bar H and the dovetail303 with the expanders 26. Such arrangement and coaction is indicated inFig. 6. Of course, with the face of the dovetail 30B rounded as shown,it may be used without the small expander 26. Each of the expanders maybe provided with a set screw 26A if desired.

Further, if desired, suitable graduations, such as are shown at 40, maybe provided on one of the nuts 20 and one of the bars l0 and II. And

by providing graduations on sleeve l6, as shown 3 at ISA, to indicatefractions of a turn of the sleeve, accurate measurements to .001 inchmay be had without resorting to the use of a micrometer.

Now having described the invention and the preferred embodiment thereof,it is to be understood that said invention is to be limited, not to thespecific details herein set forth, but only by the scope of the claimswhich follow.

I claim:

1. An inspection device for bored or drilled holes and for insidemeasurements consisting of a pair of bars having their outer edge facesparallel, one of said edge faces being provided with a longitudinaldovetail, means for moving said bars toward and from each other whilemaintaining their parallelism, and an expander bar provided with amating dovetail along one edge face whereby to fix said expander bar tosaid dovetailed bar, said expander bar having its outer edge faceparallel to the outer edge faces of said pair of bars.

2. An inspection device for bored or drilled holes and for insidemeasurements consisting of a pair of bars having their outer edge facespar- 25 allel, one of said edge faces being provided with a longitudinaldovetail, means for moving said bars toward and from each other whilemain- 4 taining their parallelism, and a plurality of expander bars ofdifferent widths each provided with dovetails along their edge faceswhereby they may be fixed to said dovetailed bar in series relation,said expander bars each having its outer edge face parallel to the outeredge faces of said pair of bars.

GEORGE D. HAYDEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

' UNITED STATES PATENTS Number Name Date 484,813 Nugent Oct. 25, 1892833,598 Hansen Oct. 16, 1906 953,282 Nash Mar. 29, 1910 1,351,528 MartinAug. 31, 1920 1,417,001 Volis May 23, 1922 2,254,894 Johansson Sept. 2,1941 FOREIGN PATENTS Number Country Date 49,000 Sweden Apr. 20, 1921136,427 Great Britain Mar. 26, 1919 554,054 Great Britain June 17, 1943

